The same installer should work for both 32 and 64 bits operating systems. If you encountered problems using the installer on 64 bits systems, please elaborate.
I'd like to have more details regarding tamper protection not being able to protect Sophos Management Communication System.
1) About the agent. The message should be changed from "32 bits" to "32/64 bits". Or maybe change the text for other more explained.
2) Tamper Protection:
See the attached image. Tamper protection "protect" the Sophos Anti-Virus and Sophos Auto-Update uninstall but the Sophos Management Communication System was unistalled.